GigaSpaces Cloudify Any App, On Any Cloud, Your Way February 2012 Using Groovy in Cloudify The why, the where and the how Barak Merimovich Cloudify Team Leader GigaSpaces

Cloudify – A quick overview What is a DSL? Why use a DSL for Cloudify Recipes? Why Groovy? The Cloudify Groovy DSL ® Copyright 2012 GigaSpaces Ltd. All Rights Reserved 2 AGENDA

® Copyright 2012 GigaSpaces Ltd. All Rights Reserved3 Using Recipes Cloudify On-Boards Any App Onto Any Cloud Unchanged CLOUDIFYING ENTERPRISE APPLICATIONS IS EASY

CLOUDIFY CREATES VIRTUAL MACHINES AND INSTALLS AGENTS ® Copyright 2012 GigaSpaces Ltd. All Rights Reserved4

CLOUDIFY AGENTS INSTALL AND MANAGE YOUR APPLICATION ® Copyright 2012 GigaSpaces Ltd. All Rights Reserved5

APPLICATION DESCRIPTION THROUGH RECIPES ® Copyright 2012 GigaSpaces Ltd. All Rights Reserved6 Recipe DSL Lifecycle scripts Availability & Monitoring Probes Custom plug-ins(optional) application { name="petclinic" service { name = "mongod" } service { name = "mongoConfig" } service { name = "apacheLB" } service { name = "mongos" dependsOn = ["mongoConfig", "mongod"] } service { name = "tomcat" dependsOn = ["mongos","apacheLB"] }

APPLICATION DESCRIPTION THROUGH RECIPES ® Copyright 2012 GigaSpaces Ltd. All Rights Reserved7 Recipe DSL Lifecycle scripts Availability & Monitoring Probes Custom plug-ins(optional) service { name "mysql" icon "mysql.png" type "DATABASE"... }

APPLICATION DESCRIPTION THROUGH RECIPES ® Copyright 2012 GigaSpaces Ltd. All Rights Reserved8 Recipe DSL Lifecycle scripts Availability & Monitoring Probes Custom plug-ins(optional) Lifecycle { install "mysql_install.groovy" start "mysql_start.groovy" startDetectionTimeoutSecs 900 startDetection "mysql_startDetection.groovy" stopDetection { !ServiceUtils.isPortOccupied(jdbcPort) } preStop ([ "Win.*":"killAllMysql.bat", "Linux.*":"mysql_stop.groovy ]) shutdown ([ "Linux.*":"mysql_uninstall.groovy" ]) }

APPLICATION DESCRIPTION THROUGH RECIPES ® Copyright 2012 GigaSpaces Ltd. All Rights Reserved9 Recipe DSL Lifecycle scripts Availability & Monitoring Probes Custom plug-ins(optional) monitors { def ctxPath = ("default" == context.applicationName)?"":"${context.applicationName} def metricNamesToMBeansNames = [ "Current Http Threads Busy": ["Catalina:type=ThreadPool,name=\"http-bio-${currHttpPort}\"", "currentThreadsBusy"], "Current Http Thread Count": ["Catalina:type=ThreadPool,name=\"http-bio-${currHttpPort}\"", "currentThreadCount"], return getJmxMetrics(" ",currJmxPort,metricNamesToMBeansNames) }

APPLICATION DESCRIPTION THROUGH RECIPES ® Copyright 2012 GigaSpaces Ltd. All Rights Reserved10 Recipe DSL Lifecycle scripts Availability & Monitoring Probes Custom plug-ins(optional) scalingRules ([ scalingRule { serviceStatistics { metric "Total Requests Count" statistics Statistics.maximumThroughput movingTimeRangeInSeconds 20 } highThreshold { value 1 instancesIncrease 1 } lowThreshold { value 0.2 instancesDecrease 1 } ])

APPLICATION DESCRIPTION THROUGH RECIPES ® Copyright 2012 GigaSpaces Ltd. All Rights Reserved11 Recipe DSL Lifecycle scripts Availability & Monitoring Probes Custom plug-ins(optional)

WHAT IS A DSL? ® Copyright 2012 GigaSpaces Ltd. All Rights Reserved12 A domain-specific language (DSL) is a programming language or specification language dedicated to a particular problem domain, a particular problem representation technique, and/or a particular solution technique. Some examples: SQL UML XSLT

WHY USE A DSL – PRODUCT REQUIREMENTS ® Copyright 2012 GigaSpaces Ltd. All Rights Reserved13 The Cloudify Domain model is complex – Need to model the complete lifecycle of a service: machine startup, bootstrapping, installation, etc… Target audience is devops, though not necessarily dev… Keep It Simple. Recipe needs to be easy to read, modify and validate. But allow for complex use cases for power users.

WHY USE A DSL – TECHNICAL REQUIREMENTS ® Copyright 2012 GigaSpaces Ltd. All Rights Reserved14 Strongly typed domain model Easy to use objects in code Easy to validate Easy to modify domain model without changing parser code Ideally, adding new fields to existing objects should require no additional code. Allow code snippets inside configuration file (mySpecialField_ + someVariable) But dont want to write a full fledged language Developer tools – IDE, Code completion

WHY GROOVY ® Copyright 2012 GigaSpaces Ltd. All Rights Reserved15

SOME GROOVY CONCEPTS ® Copyright 2012 GigaSpaces Ltd. All Rights Reserved16 Groovy is an object-oriented programming language for the Java platform. It is dynamically compiled to Java Virtual Machine (JVM) bytecode and interoperates with other Java code and libraries. A Groovy script is fully parsed, compiled, and generated before execution (similar to Perl and Ruby). This occurs under the hood, and the compiled version is not saved. Each attribute/method invocation in Groovy goes through the metaclass registry. Enables changing a class at runtime.

GROOVY IS VERY DSL FRIENDLY ® Copyright 2012 GigaSpaces Ltd. All Rights Reserved17 Groovy's syntax allows to omit parentheses and dots in some situations. This: take(coffee).with(sugar, milk).and(liquor) Is equivalent to: take coffee with sugar, milk and liquor Closures - similar to a "method pointer", enabling code to be written and run in a later point in time. For example: def operations = { declare 5 sum 4 divide 3 print }

GROOVY FEATURES WE REALLY LIKED ® Copyright 2012 GigaSpaces Ltd. All Rights Reserved18 Allows overriding getProperty(), propertyMissing() among others, Enables intercepting calls to an object and specifying an action for them Native syntax for lists and maps. def someList = [My value', Your Value'] def someMap = [ Some Key' : 31, Some Other Key' : 28] Expressions embedded inside strings println Hello ${world} Native support for various languages XML – useful for manipulating configuration files. ANT – just plain useful.

LOADING A GROOVY DSL FILE FROM JAVA ® Copyright 2012 GigaSpaces Ltd. All Rights Reserved19 The most important class you should know is groovy.lang.GroovyShell Easiest example of usage: Object result = new GroovyShell().evaluate(new File(path)) This runs the groovy runtime with the given file, just like running the groovy command line. Now lets tweak the shell to process our DSL Format.

LETS START WITH A BASIC GROOVY FILE ® Copyright 2012 GigaSpaces Ltd. All Rights Reserved20

USE CONSTRUCTOR WITH NAMED PARAMETERS ® Copyright 2012 GigaSpaces Ltd. All Rights Reserved21

ADD IMPORT CUSTOMIZER TO GROOVY SHELL ® Copyright 2012 GigaSpaces Ltd. All Rights Reserved22

BETTER, BUT NEEDS A BIT MORE ® Copyright 2012 GigaSpaces Ltd. All Rights Reserved23

OVERRIDE SCRIPT BASE CLASS ® Copyright 2012 GigaSpaces Ltd. All Rights Reserved24 A Groovy script is compiled into a Java class. The Groovy commands run in the run() method. The created Groovy class extends the groovy.lang.Script class. Default implementations of: get/setProperty invokeMethod println Use GroovyShell to replace default base script class with our own implementation.

OVERRIDE SCRIPT BASE CLASS ® Copyright 2012 GigaSpaces Ltd. All Rights Reserved25 Tweak a few small things, like redirecting println() to Logger

AND TWEAK SOME MORE ® Copyright 2012 GigaSpaces Ltd. All Rights Reserved26 Override invokeMethod() and setProperty() Map method names to domain objects If not a domain object, map to field name of current object

LOAD AN OPTIONAL PROPERTIES FILE AND BIND TO SHELL ® Copyright 2012 GigaSpaces Ltd. All Rights Reserved27 Bind to Groovy Shell

EASY TO READ, BUT STILL POWERFUL ® Copyright 2012 GigaSpaces Ltd. All Rights Reserved28

GRAB THE CODE ® Copyright 2012 GigaSpaces Ltd. All Rights Reserved29 The Cloudify web site: And on github: See the actual code: n/java/org/cloudifysource/dsl/internal/DSLReader.java n/java/org/cloudifysource/dsl/internal/DSLReader.java n/java/org/cloudifysource/dsl/internal/BaseDslScript.java n/java/org/cloudifysource/dsl/internal/BaseDslScript.java

QUESTIONS ® Copyright 2012 GigaSpaces Ltd. All Rights Reserved30 The Cloudify dev team is available on the Cloudify forum: and bug tracker: